This invention relates to an axle bearing apparatus, and more particularly to an axle bearing apparatus having muddy water intrusion prevention means for preventing muddy water from intruding into a bearing portion.
Recently, unit-type axle bearing apparatuses have increasingly been used even in a pickup truck, etc., and therefore these bearing apparatuses are required to have a higher muddy water-proof ability.
There is known an axle bearing apparatus having such a muddy water-proof ability, in which a seal ring comprising a metal core and a seal member is fixed to an outer end portion of an outer ring of a bearing portion, and a slinger is fixed to an axial inner side surface of a rotary flange, and is held in sliding contact with the seal ring, thereby closing an opening of the bearing portion (see, for example, JP-A-2005-233287).
In the axle bearing apparatus of JP-A-2005-233287, an annular portion of the slinger is not disposed in intimate contact with the axial inner side surface of the rotary flange, and extends merely to a region disposed radially inwardly of a circle of bolt holes formed in the rotary flange. Therefore, there has been a fear that muddy water might intrude into the bearing portion from the outside of the rotary flange and the bolt holes through a clearance between the rotary flange and the annular portion of the slinger.